Swim fins are typically worn by swimmers and those engaged in snorkelling and scuba diving in order to provide a means to increase their rate of propulsion through the water. Most commonly swim fins comprise a blade or web portion that is either fixed to a boot that may worn by the swimmer or that is otherwise attachable to a swimmer's foot. The blade on the fin increases the amount of water that is displaced during a kicking movement and thereby increases the acceleration and propulsion of the swimmer through the water.
Traditionally, swim fins have been designed with the blade or web portion rigidly fixed to a boot or toe portion that is attachable to a swimmer's foot. More recently, articulated swim fins have been developed, such as those described in U.S. Pat. No. 5,632,662, dated May 27, 1997. In that patent there is described a fin wherein the blade or web portion is pivotable about a hinge joint on the boot in order to allow for forward propulsion during a kicking movement, while at the same time relieving the stress and strain that would otherwise be applied to the ankle and foot of the swimmer through the use of a traditional fixed blade fin. While such fins may be advantageous in terms of relieving muscle strain and fatigue of the ankle joint, they nevertheless suffer from a common and inherent limitation associated with fins having blade portions that are permanently secured to a boot portion.
Swim fins, whether they be traditional swim fins or more recently developed centrally articulated fins, are clumsy and difficult to manipulate when walking on land. Previous attempts to design a swim fin that allows a swimmer to more easily walk on land have met with only limited success and have focussed upon the use of relatively complex mechanical structures that permit the blade or web portion of the fin to pivot upwardly to a position above the swimmer's foot (for example see U.S. Pat. No. 4,981,454, dated Jan. 1, 1991). Such fins are not only more mechanically complex, and as a result more prone to failure, but are also generally more expensive to manufacture and often enhance the ease of a swimmer to walk on dry land at the expense of comfort and simplicity of use.